Storage Manager is the image control dashboard. Users can upload/remove images and folders. After loading images, users can use their images in their sites using CDN images. It automatically distributes the images around the globe.
Storage Manages has two section: File Manager and Assets (Folders and Images).
First section is the File Manager which is responsible of the uploading images. You can get more detailed explaination in How to Upload an Image.
Second section displays the users Assets - Folders and Images. Users manages their uploaded images and their folders. You can organize your images using folders. You can check out more on Working With Folders and Using Uploaded Images.